Internal combustion engine of the compression ignition type



March 31, 1942- F. coLELL 2,278,245. 'i

INTERNAL COMBUSTION ENGINE ^OF THE COMPRESSION IGNITION TYPE Filed Feb.V5, 1959 havo( T; iedvh-CO le,

NVENVOR,

Parente' Manci; 194?.`

',INTERNALCOMBUSTION ENGlNE Ortner;l x CoivIPnESSVIoNj-IGiSiTIIQNLTYBE iRichard iedrch eeil', dgiial'sto'; isiriinnr-v ham,EnglandgpassignontolThe-Austin Motor Company, Limited, Northfield,Birmingham,

England.,

A InyGreatzBritain February I5, 1938` selanaflcl. 10a-i141): Thevinventionr relates v:internal ,combustion Q engines ofthe Dieselorcompression ignitionf type. Itis well known that sucheng'inesare sub-`ject to a defect,v known as Diesel Knock, caused apparently bycombustion'delay, and with a view to avoiding orV lessening thisdefect`it has been proposed to arrange forY the vvin'jectiorlfof. a smallquantity'of fuel prior to the main injection, thisv being known asapilot-'injection. It has been found that such an injection greatlylessens the effect of knock.

To effect such pilot injection', it has vipeenll'rfih-v posed to providevtwofselzvaratek fuel injection* pumps delivering fuel to two separatenozzles and through two separate v-non-returnvalves, but

such arrangement involves the use of a large number of additional partswith .increasedv errpense and weight. It has also beenproposed tovprovide two fuel pumps'supplying f uel'to a com-` mon nozzle; but thisdoes not `greatlysimplify the construction and necessitates a largevolume of fuel between thepumps and thenozzle,'and` necessitates twonon-return valves; It has also`r been proposed to provide only a singlefuel rpumpV supplyingvfuel to a single nozzle;jbut this necessif- Jitates the use of two operative surfacesona single cam which isunsatisfactory as it does-not.A leave` t sufficient time for two'iconsecutive-injections and a pause between.v f g l According to thisinvention, two pump cylinderseach having a suction port areuseda'main-pump cylinder for the main charge andra pilot pump cylinderfor the pilot charge, and the two pumps are connected in such a wayvthattheorie pumpdelivers its charge through'the suctionjport of the other,fromwhere it flows -to the nozzle via the. non-return valve'. Thus therel 'is `afirst pump, fuel from which passes through the cylin-v the mainpump.

The supply of fuel to the second pump cylinder passes through thedelivery port of the rst pump cylinder, via the cylinder andsuction-port of the i-lrst pump,v the piston of the latter pumpvbeingder of a second pump, but either of vthese` may be arranged to moveforward just priorA to, or justV after, the forward movement ofvthesecond'pisv ton, andL in such va way that the secondv piston candisplace fuel backwards into thev suctionl chamber through the rst pump.

A convenient embodiment of .the inventionv is described .with referenceto the drawing herewith which is a vertical section illustrating thefuel injection system of a compression ignition engine,

said system being arranged accordingto' the invention;l

,fuel injection' nozzle `B the 'nonqreturn l valve and eine mainfueip'umpylinder' 11i-"whichfW'i'kS the main piston D" havingl a fladfE`the dium. kof a rollerjd 4turnably` mounted ,inl @slide 10 en,@integral wants-e piston. The 1arte-r is .alge provided-with a', ipairof rm's'j 'd4 werking in a pair-of's'lots' y' in a turnablefsfleeve'Jwhich has, at yfits upper-end, spur teeth il-ve'n'gaging with/a .rackrj? moved: jby the l:engine governor, Vwhereby the vlatter'aots; .torotate thehmainfpiston, all thesepartsbeingusual,practlcei Y V Kis thefcylinder of them-pilot. umpin which works the pilot "pistonnMhaving -ahead m which also: has itsl lowerv edge vrof J helical form. Itf* alsohas agroove m1 connecting ,thespace above the frotatedfsl'milarlyas isthe 'mainfpisjton'- by'arack Ythe medium offa roller q and doublefrarmedlever the pilot cylinder Kthrough` the-Wall thereof. SV is a secondport'leading-from :the uppei'en'd of thepilot cylinder tothemainlcylinder-,C v,also

through the wallthereof.

The operation is as follows; 1 The vpilot cam operatesv first.andgrockspthe lever q1 thus causing the pilot piston t'o'"inove upf.

'A5 the space above'it isfull offfuel, the pls'tonfat first` causes fuelto flow back -tothechamber''P'I `buty the piston head in advancingcovers the-'port 1'1. when the fuel, having; no escapa-isfo'rced vlipthroughthe port'S andv-thencethrough the main cylinder C tothe-nonreturn: valve B and so. to

the fuel ,nozzlev in the .engine cylinder (not shown). As soon as thebottoni edge of thefhead of the piston' M passes the bottoin'of-.theport' the pilot injection is ,finishedand fuercan flow back via thegroove m to the chamber-P. v"Mean-- time, the cam .F' has commencedv toraise the main vpistonDand its head E movesto close the port S; butsince the head of the piston M has reopened the port R, the piston Dcan, at first, re-

turn fuel through the ports S and R to the chamber P. As soon, however,as the head E closes the port S, the fuel cannot flow back, andtherefore, further movement of the main piston forces fuel past thenon-return valve for the main charge. As soon as the bottom edge of thehead E passes the bottom of the port S, the main in- .lection isfinished, and the fuel can flow back to the chamber P via the port e,cylinder K and port R, this latter being still open. Each piston head inpassing back over its respectiveport will cause a certain amount ofvacuum in the space above; but this will be rapidly filled up as soon asboth piston heads reopen the4 ports of `their respective cylinder.

It will now be clear that the cylinder K may, if desired, be the largercylinder and act as the main pump cylinder, but in such case the other ypiston then acting as the pilot piston, must be that which moves forwardfirst, the cams being,r

so placed as to conform to this condition.

Having fully described my invention what I `claim and desire to secureby letters Patentfis:

1. In a fuel injection apparatus for use` with an engine of thecompression ignition type, the combination' of a fuel port, a non-returnvalve for the fuel port, a main fuel pump cylinder, a main pistonworking therein, a pilot pump cylinder, a pilot piston working therein,a fuel supply chamber Acommon to the aforesaid main fuel pump cylinderand pilot pump cylinder, each of said cylinders having a suction port,each cylinder also havinga delivery port, the pilot pump cylinder beingpositioned in proximity to and in communication with the main fuel pumpcylinder, said cylinders being alternately in communication with theaforesaid fuel supply chamber with which the aforesaid suction portscommunicate, whereby the piston ofthe one cylinder first causes fuel toflow back in to the common fuel supply chamber, fuel being then forcedto the other cylinder through the suction port thereof V'and from saidcylinder to the non-return valve and so to the fuel port in the enginecylinder.

l2. In a fuel injection apparatus for-v use withpiston working therein,a pilot pump cylinder, a pilot piston working therein, each cylinderhaving a suction port, a fuel supply passage alternately incommunication with the suction port ofthe pilot pump and with the mainfuel pump cylinder, either of the aforesaid pumps may deliver its chargeto the other pump cylinderthrough the suction port thereof, said fuelpassing thence to said non-return valve, the fuel passing to said otherpump cylinder and destined to be pumped by the piston of said othercylinder passing from said fuel supply chamber through said suction portof said first named cylinder and Working therein, va pilot pump cylinderana a pilot piston working therein, the pilot-pump cylpump cylinderthrough the suction port thereof,

said fuel passing thence to said non-return valve whereby fuel passingto said main pump cylinder and destined to be pumped by .the main pistonpasses from said fuel supply chamber through said-suction port of thepilot pump cylinder and thence through such cylinder and the suctionport of the main pump cylinder and whereby during the part of theforward stroke of the said main piston fuel can flowl back to theaforesaid fuel supply chamber via the pilot pump cylinder.

3. In a fuel injection apparatus for use with an engine of thecompression ignition type, the combination of a fuel p ort, a non-returnvalve for said port, a. main fuel pump cylinder, a main inder beingpositioned in proximity to the main pump cylinder, a common passageforming the outlet from Ithe one pump cylinder and the inlet to theother pump cylinder, an outlet passage from said other pump cylinderleading to the non-return.valve, a fuel supply chamber and a .passageleading therefrom tothe said one pump cylinder, whereby the on pumppiston may, at each operation, draw a charge of fuel from said chamberand force it through the other pump cylinder tothe non-return valve, andwhereby said other pump piston mayat each operation, draw a charge fromthe said one pump cylinder and, during the rst part of its forcingstroke, return a portion of the fuel to the supply chamber backthroughsaid one pump cylinder and Y during the latter part of-itsstroke forceanother portion of the fuel to the non-returnvalve.

5. In a fuel injection apparatus for-use with anengine of the fuelinjection type having, in respect of each engine cylinder, afuelinjection port and a non-return fuel valve, thecombination of a mainpump cylinder and a main piston working therein, a pilot pump cylinderand a Vpilot piston working therein, the pilot pump cylinder beingposiioned in proximity to the main pump cylinder, a common passageforming the outlet from thepilot pump cylinder and the inlet to the mainpump cylinder, an outlet passage from the main pump cylinder leading tothe nonduring the first partof its forcing stroke, return a .portion ofthe fuel to the supply chamber back through said pilot pump cylinder andduring the latter part of its stroke forcel another portion of the fuelto the non-return valve.

RICHARD FRIEDRICH COLELL.

